Ultraviolet radiation protection factors of livestock shade cloths for free-range pigs.

BACKGROUND: Protection from solar ultraviolet radiation (UVR) is paramount in light-skinned pig breeds such as Yorkshire or Landrace to avoid sunburn. OBJECTIVES: Determination of the UVR exposure of a pig and the sun protection abilities of shade cloths with different shade rates. ANIMALS: Life-sized plastic model of a Landrace pig. MATERIALS AND METHODS: The model was equipped with 20 UVR meters at various anatomical positions that recorded the erythemal effective solar irradiance. A turntable enabled irradiation from different directions. Solar irradiance was measured in direct sunlight as well as under three shade cloths with different shade rates (50%, 75% and 90%) and a camouflage net. The sun protection factors (SPF) were determined as the ratio of unshaded-to-shaded measurements at the same solar elevation. The exposure ratio to ambient (ERTA) was calculated for each body site with respect to ambient irradiance. It allows determination of when pigs are at risk of sunburn and protection is needed. RESULTS: The calculated ERTA values show that some body parts may receive higher values than ambient UVR. Measurements showed that the SPF of shade cloths depends on textile denseness. Selected shade cloths reached values of 3.5 (shade rate 50%), 4.2 (75%) and 5.8 (90%). Protection by the camouflage net was poor. The highest SPF was gained on body sides where ERTA was highest. CONCLUSIONS AND CLINICAL RELEVANCE: Shade cloths can protect all body sites effectively and vulnerable sites in particular. The results of our study enable an estimation of when pigs are at risk of sunburn and provide quantitative metrics for sun protection. This allows effective prevention of UVR-caused skin damage and secondary disorders.

UV-Biometer - The usage of erythemal weighted broadband meters for other biological effects.

In this paper, we pick up the idea of the "UV-Biometer": the use of erythemal weighted broadband meters for other photobiological endpoints. Therefore, nine different types of broadband meters were considered. A necessity for their calibration is the availability of an action spectrum for the respective effect over the complete solar ultraviolet (UV) radiation range. Unfortunately, such action spectra are rather rare. Here we used the action spectra for non-melanoma skin cancer, DNA-damage, clearing of psoriasis, ICNIRP's workers protection and persistent pigmentation. The action spectrum for vitamin D photosynthesis is taken to estimate the effect of missing effectiveness values in the UV-A range. Application shows that high uncertainties occur especially at low solar elevations. Calibration factors in dependence of total ozone and solar elevation were calculated for all broadband meters and all effects. Analysis shows, that not all of these effects are as appropriate as erythema. The calibration for all effects was applied for a broadband meter that measures the UV-Index operationally within the Austrian UV-Index network. As most of these action spectra have threshold limit values or minimum dose equivalents, irradiance was converted into threshold exposure times. Uncertainties from total ozone during routine operation are estimated. Additionally, we derived conversion factors for erythemally effective irradiance to these effective irradiances. This delivers an easy way to gain biologically effective irradiance without the need of knowing the properties of the instrument. However, this introduces additional uncertainties and not all conversions should be applied.

Personal UVR exposure of farming families in four European countries.

BACKGROUND: The main risk factor for skin cancer is ultraviolet radiation (UVR). Farming families living in rural areas with easy outdoor access may experience excessive UVR exposure. Differences between countries in latitude, altitude and sun behaviour could result in different personal UVR exposures. However, no studies have examined this until now. OBJECTIVES: To determine personal UVR exposure in work and leisure situations among farming families in Europe. METHODS: Prospective cohort study of farmers, their partners (spouses) and children in Denmark (DK), Poland (PL), Austria (AT), and Spain (ES) from 2009 to 2011. Personal UVR exposure and sun behaviour were recorded by dosimetry and diaries. RESULTS: Farmers' average daily UVR exposure on working days ranged from 1.4 SED (DK, AT) to 2.7 SED (ES). Corresponding figures for partners were: 0.6 SED (DK) to 1.9 SED (PL), and for children (day-care/school days): 0.7 SED (ES) to 1.3 SED (PL). DISCUSSION AND CONCLUSIONS: Farmers' UVR exposure was comparable to that of outdoor workers in previous studies and exceeded the recommended UVR exposure limits on 36% (DK, AT), 29% (PL) and 56% (ES) of their working days. Attention to sun protection for outdoor workers across Europe in preventing UVR-induced skin cancer is still needed.